Makes Embed() take a single node

mojo/services/view_manager/test_change_tracker.cc

Index: mojo/services/view_manager/test_change_tracker.cc
diff --git a/mojo/services/view_manager/test_change_tracker.cc b/mojo/services/view_manager/test_change_tracker.cc
index 89e7fbb44459b3c5407ec43b7827d5de0f06d588..8263dc45281b2743bf97cd7d2d09056df994a9e4 100644
--- a/mojo/services/view_manager/test_change_tracker.cc
+++ b/mojo/services/view_manager/test_change_tracker.cc
@@ -37,7 +37,7 @@ std::string ChangeToDescription1(const Change& change) {
                                 change.creator_url.data());
 
     case CHANGE_TYPE_ROOTS_ADDED:
-      return "OnRootsAdded";
+      return "OnRootAdded";
 
     case CHANGE_TYPE_SERVER_CHANGE_ID_ADVANCED:
       return base::StringPrintf(
@@ -158,7 +158,7 @@ void TestChangeTracker::OnViewManagerConnectionEstablished(
   AddChange(change);
 }
 
-void TestChangeTracker::OnRootsAdded(Array<NodeDataPtr> nodes) {
+void TestChangeTracker::OnRootAdded(Array<NodeDataPtr> nodes) {
   Change change;
   change.type = CHANGE_TYPE_ROOTS_ADDED;
   NodeDatasToTestNodes(nodes, &change.nodes);